The goal of this project is to characterize and understand how spatial auditory perception is altered by past experience. Experiments will test the hypothesis that spatial auditory processing is hierarchical and that experience influences spatial perception through different mechanisms at different processing stages. Specifically, experiments will test whether 1) explicit training rapidly alters how spatial percepts are mapped to perceived locations in exocentric space; whereas 2) implicit learning of room acoustics alters how spatial cues are integrated to form spatial percepts, leading to improvements in localization reliability with experience in a room; and 3) early stages of the pathway do not change, but include dynamic, nonlinear effects that alter what information is available to later processing stages. These hypotheses will be addressed through behavioral experiments that measure spatial localization accuracy and variability, acoustic measurements that characterize how spatial acoustic cues are affected by different acoustical environments, and computational models that explore what processing structures account for experimental results. This work is critical for identifying how the normal human listener adapts and calibrates spatial perception in everyday settings in order to maintain accurate spatial perception in changing acoustic environments. Results will help to elucidate how past experience influences spatial auditory processing, changes spatial auditory perception, and affects spatial resolution and localization accuracy. By studying perceptual phenomena that reflect changes at different stages of processing and affect behavior over a range of time scales, this project will provide a coherent picture of how the normal auditory system keeps spatial auditory percepts in registry with percepts from other modalities.